This invention relates to a process and apparatus for forming a film or sheet-like product from thermoplastic synthetic resin compositions by the employment of the conventional extruders even when the resin compositions include reclaimed synthetic resins having relatively low thermal decomposition temperatures and more particularly, to a multilayer laminated resin which comprises top and bottom outer layers of sandwich structure each consisting of a first resin of reclaimed synthetic resin entirely surrounded by a second resin of fresh resin and an inner layer of a third resin having a property different from those of the above-mentioned two resins interposed between and secured to the top and bottom outer layers and a process and apparatus for producing the multi-layer laminated resin film.
Of late, synthetic resins have been required to have one or more of a variety of properties depending upon applications of such resins and these properties include moldability, transparence, printability, impact resistance, weather resistance, tensile strength, elongation, shearing strength, adhesion and gas permeability and novel resins have been developed to meet these requirements. However, difficulties have been encountered in producing resins having two or more of the above-mentioned properties and even when such resins were developed, they could not be commercially produced.
Thus, in order to meet the above-mentioned requirements, there have been proposed relatively less expensive laminated resin films which are excellent in some of the above-mentioned properties called for in resins and one example of these laminated resin films is a heat sealable auto-packing laminated resin film which comprises opposite outer layers formed of polyethylene having excellent heat sealing property and an inner layer formed of polyethylene having high recilience and tensile strength in a thin film form because the polyethylene forming the outer layers is insufficient in resilience and tensile strength. Alternatvely, there has been also proposed a laminated resin film which comprises opposite outer layers formed of polyethylene and an inner layer formed of vinylidene chloride of low gas permeability because the polyethylene forming the outer layers is excellent in heat sealing property, but high in gas permeability. When these laminated resin films formed of two or more different synthetic resins are employed in the producing of certain products, some rejects are inevitably produced and discarded as waste and when the laminated resin films are stamped to produce certain products, waste or scrap is produced.
And since the decomposition temperatures of various waste synthetic resin materials are in many cases lower than that of any one of laminated films formed of a plurality of different materials and the properties of such waste materials are unknown, such resin waste materials are discarded without being reclaimed.